1. Field of the Invention
The invention pertains to the field of pressure indicators.
2. Background of the Invention
Many vending machines and other devices contain gas pressure distribution systems which receive their pressure from a replaceable gas supply. These gas supplies, very often carbon dioxide canisters, are replaced when a needle on a pressure gauge indicates that system pressure is too low for proper functioning.
While conventional gauges with a needle and a dial provide an adequate and accurate indication of system pressure, they are usually located within a closed unit and not monitored until the unit malfunctions.
Once a unit malfunctions, due to low pressure, an emergency service call is needed to restore it to operation as soon as possible.
Emergency service calls are expensive from a labor standpoint and represent a period of loss of machine service. On the other hand, it is undesirable to provide an additional pressure monitoring system that will substantially raise the cost of the machinery or perhaps impair the integrity of the pressure system.
There has thus been a need for an inexpensive, external, threshold monitoring system that might be installed on existing pressure systems, utilizing the available conventional pressure gauge, to provide a remote low pressure indicator.